Also, just out of curiosity, these "Desired values" on the test, are they generic values, values geared towards crops, are they in any way relevant for turf?

j4 said: The Logan Labs methodology indicates a slice of soil should be taken from 1" to 4", so I sent in another sample...

Where does Logan say that? Morpheus does that because he has crazy soil and he's sampling below 1" for other reasons. You are supposed to sample from soil surface down to your 4". I'm guessing your organics must be a little higher than 2% due to the missed top 1". I'm guessing your mineral amendments are probably still in the top 1" of soil. I'd consult morpheus before adding anything more. Boron washes away easily, so maybe that's why that number came up nicely i in the >1" depth sample.

I'm a little confused. Are you self-medicating or making additions based on a read and recommendations from morpheuspa? If on recommendations, are they based on the June test or a prior test?

I'm a little confused. Are you self-medicating or making additions based on a read and recommendations from morpheuspa? If on recommendations, are they based on the June test or a prior test?

I'm making additions based on the read of the June test from Morpheus, with slight adjustments ( e.g. muriate of potash instead of potassium sulfate) based on what I have on hand. I posted the link to the original thread above.

Soooooo... do I put more lime down?

The other forum recommends sampling from between 3"-4", so I guess the first one is right?

I think either way, the top inch should be excluded because it will badly skew the OM - especially if using organic fertilizer. 90% of the root mass is below that top inch where a lot of OM (most of it actively decomposing and subject to loss as CO2) is concentrated. Kind of like having 5 people that make $20,000 a year and one that makes $1,000,000 and saying the average salary is $183,000. Mathematically true, but quite misleading.

I guess sampling including the top inch would be ok in a tilling situation where it constantly gets mixed in, which would explain why LL recommends taking the soil sample the way they do.

Thank you. I will stay the course.

Why is the potassium so much higher deeper down than in the top layers? Calcium is the opposite, is there a relationship between the two?

There's really no relationship, and it's a case where I don't have a pat explanation. Potassium doesn't wash out all that easily--and neither does calcium (K a little easier than Ca, though). Over time, that could create some differential, but I wouldn't expect that much.

In this case, I'm content to wait for the next soil test next year to get a third read to break the "tie"--and fortunately, a little extra K doesn't particularly worry me. It's not a water pollutant, and the band of optimal to luxury consumption is extremely wide. Toxicity won't be an issue.

I have another one for you, what are your thoughts on feeding potassium via foliar spray? Maybe not chloride but sulfate. Give the grass a boost until soil levels come up a little.

Edit: potassium nitrate looks like a good candidate. Ferrous Potassium Nitrate (FPN) instead of FAS?

I'm neutral to slightly negative on it. Foliar feeding works really well on trace elements, or as a minor and very temporary pick-me-up. For the top nutrients (nitrogen, potassium, phosphorus, and calcium, in that order, plus borderline on sulfur), the plant simply can't absorb enough through their leaves because not enough mass sits on the plant.

Rather than expend the effort, I'd just add it to the soil and, if I wanted it to work fast, water it in.

Potassium nitrate would be a fine source of both K and N if you want to use it, though! Assuming you can find it at a reasonable price...it looks far more expensive than using urea and potassium sulfate.

To recap, in June I took a sample from 4" -4.5". The Logan Labs
methodology indicates a slice of soil should be taken from 1" to 4", so I
sent in another sample using that method to see if any differences.

The other forum recommends sampling from between 3"-4", so I guess the first one is right?

I guess sampling including the top inch would be ok in a tilling
situation where it constantly gets mixed in, which would explain why LL
recommends taking the soil sample the way they do.

Pick your poison. As long as the sample is representative of the root zone, all that matters is that you stay consistent for subsequent soil tests. 1-4" is likely to be more representative of a profile of the root zone by averaging than a 4-4.5" sample. Same reason you should sample multiple areas rather than a single hole. It's horse shoes, not darts anyway.

Subsequent to the initial test (if it was done on an undisturbed and not recently amended lawn where nutrient levels would be fairly consistent throughout the root zone depth), once amendments (which are calculated for amounts to change the full root zone profile) are added, your soil is going to have different nutrient depth horizons in subsequent tests. How much soil is affected by an amendment varies. On a scale of 1-10, slow to fast for movement into the soil, N would be a 10 (boron would be as fast or faster), K would be a 3 and P, a 1. It is estimated that amendments (for instance K, P and lime) will infiltrate and affect about one inch of soil per year in a CEC10-15 soil. Sands will be much greater, clays, less in affected annual depth. So, depending on your soil texture, you might see a change in nutrient levels in a year or two or in three or for years, if ever, at the 4+" depth. Also, keep in mind that many times the total amount of a needed nutrient shouldn't be added in one dose and will be applied over a year or two in order to meet the desired levels throughout the depth of the root zone.

@yardtractor1

Great info, thank you. I guess that's why in agricultural situations all this stuff gets tilled in.

>>On a scale of 1-10, slow to fast for movement into the soil, N would be a 10 (boron would be as fast or faster), K would be a 3 and P, a 1.

Actually, this isn't accurate. N will vary:

Urea--about a 9. It hitches up in the soil just a tiny bit as compared to nitrates.

Ammoniacal nitrogen--about a 2. It binds to CEC points.

Nitrate and Nitrite: 10, but it does depend; ample bacterial soil life can slow this down considerably by absorbing and binding it (nitrogen retention is one good reason to keep OM levels good and soil life at high levels of activity and population).

K and P certainly are about a 3 and 1 respectively...if P is even as fast as a 1!

Boron, being positively charged, binds very easily, but does wash out. Call it a 4, but certainly not a 10, and about twice as easily as sodium's 2-ish.

Elements that bind to CEC points, or to soil particles or into insoluble compounds, don't move very easily. So overwhelming the soil's ability to bind the nutrient, or working with a wildly off pH, will certainly change the above.